To determine 1)the changes in BMC in newborn infants at various gestational ages and to compare the changes in BMC postnatally between infants born at term and prematurely, 2)the relationship of total body with regional mineral content 3) the relationship of the change in BMC with a)standard anthropometric measurements, b)gender, race gestational age, postnatal ages and season at measurements, c) type and duration of various nutrient intakes and therapies that may interfere with bone mineralization.